PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch General Description Features The AAT4687 OVPSwitchTM is a member of AnalogicTech's Application Specific Power MOSFETTM (ASPMTM) product family. It is a P-channel MOSFET power switch with precise over-voltage protection control, designed to protect low-voltage systems against high-voltage faults up to +28V. If the input voltage exceeds the programmed over-voltage threshold, the P-channel MOSFET switch will be turned off to prevent the output load circuits from damage. The AAT4687 is available with an internally programmed over-voltage trip point or as an adjustable version programmed by two external resistors. * * * * The AAT4687 includes an under-voltage lockout (UVLO) protection circuit, which will put the device into sleep mode at low input voltages only consuming < 1A of current. The AAT4687 also includes an enable pin (EN) to enable or disable the device and an OVP, OTP fault indicator (FLT). The AAT4687 is offered in a small Pb-free, 10 pin SC70JW package, and is specified for operation over the -40C to +85C ambient temperature range. * * * * * * * Over-Voltage Protection up to 28V Fixed or Adjustable Over-Voltage Protection Threshold 3V Under-Voltage Lockout Threshold Fast OVP Response: 0.7s Typical to Over-Voltage Transient Low Operation Quiescent Current 30A Typical 1A Max in Shutdown (Disabled) Thermal Shutdown Protection 100m Typical (130m Max) RDS(ON) at 5V OVP, OTP Fault Indicator 1.8A Maximum Continuous Current Temperature Range: -40C to 85C Available in SC70JW-10 Package Applications * * * * * * Cell Phones Digital Still Cameras GPS MP3 Players Personal Data Assistants (PDA) USB Hot Swap/Live Insertion Device Typical Application (Adjustable Version) VIO +5V VIN 3V - 28V IN CIN 1F R1 4687.2009.09.1.0 AAT4687 FLT OVP R2 VOUT COUT 1F OUT EN GND www.analogictech.com Fault Flag 1 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Pin Descriptions Pin Number Adjustable Fixed Symbol 1 N/C OVP 2, 8, 9, 10 GND 3 FLT 4 EN 5 6, 7 IN OUT Function Over-voltage protection threshold input (Adjustable only). In the fixed version, this pin is not connected. Ground connection pin. Over-voltage or over-temperature fault reporting output pin. Open drain. FLT goes low when input voltage exceeds the over-voltage threshold or an over-temperature fault occurs. An external pull up resistor to VIO (6.5V max) should be added. Enable input pin, active low. An internal pull-down resistor is connected on this pin. Connect to ground for normal operation. Connect to high (6.5V max) to shut down the device, which then draws less than 1A of current. Power input pin. Connect 1F capacitor from IN to GND. Output. Connect a 0.1F~47uF capacitor from OUT to GND. Pin Configuration SC70JW-10 Adjustable Version (Top View) OVP GND FLT EN IN 2 1 10 2 9 3 8 4 7 5 6 SC70JW-10 Fixed Version (Top View) N/C GND FLT EN IN GND GND GND OUT OUT www.analogictech.com 1 10 2 9 3 8 4 7 5 6 GND GND GND OUT OUT 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Absolute Maximum Ratings1 Symbol VIN VOVP VFLT, VEN VOUT IMAX TJ TSTG TLEAD Description IN to GND OVP to GND FLT, EN to GND OUT to GND Maximum Continuous Switch Current Operating Junction Temperature Range Storage Temperature Maximum Soldering Temperature (at Leads) Value Units -0.3 to 30 -0.3 to 6.5 -0.3 to 6.5 -0.3 to VIN + 0.3 1.8 -40 to 150 -40 to 150 300 V V V V A C C C Value Units 160 625 C/W mW Thermal Characteristics Symbol JA PD Description Maximum Thermal Resistance2 Maximum Power Dissipation2, 3 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on a FR4 board. 3. Derate 6.25mW/C above 25C. 4687.2009.09.1.0 www.analogictech.com 3 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Electrical Characteristics1 VIN = 5V, TA = -40 to 85C unless otherwise noted. Typical values are at TA = 25C. Symbol Description Conditions VIN_MAX Input Over-Voltage Protection Range VIN Normal Operation Voltage Range IQ Operation Quiescent Current ISD(OFF) Shutdown Supply Current VUVLO Under-Voltage Lockout Threshold VUVLO_HYS Under-Voltage Lockout Threshold Hysteresis Adjustable Over-Voltage Lockout Threshold, OVP Pin VOVP_TH Over-Voltage Lockout Threshold Hysteresis, VOVP_HYS OVP Pin Fixed VOVPT Over-Voltage Lockout Threshold, IN Pin Over-Voltage Lockout Threshold Hysteresis, VOVP_HYS IN Pin MOSFET Switch RDS(ON) PMOS On-Resistance ID(OFF) Switch Off-Leakage Logic VEN(L) EN Input Low Voltage VEN(H) EN Input High Voltage IEN EN Input Leakage FLTOL FLT Output Voltage Low FLTIOL FLT Output Leakage Current Timing TBLK_FLT FLT Blanking Time FLT Assertion Delay Time from Over-Voltage TD_FLT (OV) TRLS_OV Over-Voltage Release Time TRESP_OV Over-Voltage Response Time Turn On Delay Time TON TR Turn On Rise Time TOFF Turn Off Delay Time TF Turn Off Fall Time Thermal Protection Shutdown Temperature TSHDN THYS Over-Temperature Shutdown Hysteresis Min Typ Max Units 30 28 14 60 1 3.3 V V A A V V 1.117 V 3 VIN = 5V, EN = 0V, IOUT = 0 EN = VIN, VIN = 5.5V, VOUT = 0V Rising Edge Rising Edge 3.0 0.1 1.084 Rising Edge 1.1 23 mV 6.51 V % of VOVPT 2.1 IOUT = 1500mA, TA = 25C EN = VIN 100 130 1 m A 0.4 0.5 2.0 0.4 1 V V A V A 10 15 ms 1.6 VEN = 5.5V or 0V IFLT = 1mA From De-assertion of OV 5 From Assertion of OV VIN = 5V, VOVP fall from 1.13V to 1.07V in 1ns VIN = 5V, VOVP rise from 1.07V to 1.13V in 1ns VIN = 5V; ROUT = 10; COUT = 1F VIN = 5V; ROUT = 10; COUT = 1F VIN = 5V; ROUT = 10; COUT = 1F VIN = 5V; ROUT = 10; COUT = 1F 1 5 10 s 15 ms 0.7 s 10 1 9 4.5 ms ms ms ms 150 20 C C 1. Fixed OVP Threshold Voltage Version is available from 5V to 14V at 50mV step. 4 www.analogictech.com 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Timing Diagram IN VOVPT VOVPT TD_FLT TBLK_FLT FLT TRESP_OV TRLS_OV OUT 50% EN TOFF TON 90% 50% OUT 50% 10% TR 4687.2009.09.1.0 90% 10% www.analogictech.com TF 5 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Typical Characteristics Operation Quiescent Current vs. Supply Voltage Operation Quiescent Current vs. Temperature (VIN = 5V; No Load) 40 Quiescent Current (A) Quiescent Current (A) 90 80 70 60 50 40 30 20 35 30 25 20 15 10 3 4 5 6 7 8 9 10 11 12 13 -40 14 -15 3.6 3 2.4 1.8 1.2 0.6 0 8 10 12 14 16 18 20 22 24 26 28 0.42 0.35 0.28 0.21 0.14 0.07 0.00 -40 -15 Switch Off Leakage vs. Supply Voltage 35 60 85 PMOS On-Resistance vs. Temperature (VIN = 5V, 1A Load) 160 0.014 0.012 On-Resistance (m) Switch Off Leakage Current (A) 10 Temperature (C) Supply Voltage (V) 0.010 0.008 0.006 0.004 0.002 0.000 2 4 6 8 10 12 14 16 18 20 22 24 26 28 140 120 100 80 60 -40 -15 10 35 60 85 Temperature (C) Supply Voltage (V) 6 85 (VIN = 6.5V) 4.2 6 60 Shutdown Supply Current vs. Temperature Shutdown Supply Current (A) Shutdown Supply Current (A) Shutdown Supply Current vs. Supply Voltage 4 35 Temperature (C) Supply Voltage (V) 2 10 www.analogictech.com 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Typical Characteristics FLT Blanking Time vs. Temperature FLT Blanking Time (VIN = 5V, COUT = 1F, OVP Transient from 1.2V to 0.8V, RO = 10) 13 OVP (1V/div) TBLK_FLT (ms) 12 VOUT (2V/div) IOUT (500mA/div) 11 10 9 8 FLT (5V/div) 7 -40 -15 10 35 60 85 Temperature (C) Time (2ms/div) Under-Voltage Lockout Threshold vs. Temperature Over-Voltage Release Time vs. Temperature (VIN = 5V, COUT = 1F, RO = 10) 13 UVLO_Hi UVLO_Low 3.30 12 TRLS_OV (ms) UVLO Threshold (V) 3.50 3.10 2.90 10 9 2.70 2.50 -40 11 8 -15 10 35 60 -40 85 -15 35 60 85 Temperature (C) Temperature (C) Over-Voltage Lockout Threshold vs. Temperature Over-Voltage Response Time vs. Temperature (VIN = 5V) 1.12 800 OVP_Threshold_Hi OVP_Threshold_Low 1.11 750 1.10 TRESP_OV (ns) OVP Threshold (V) 10 1.09 1.08 1.07 700 650 600 1.06 1.05 -40 -15 10 35 60 85 550 -40 10 35 60 85 Temperature (C) Temperature (C) 4687.2009.09.1.0 -15 www.analogictech.com 7 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Typical Characteristics EN Input Low Voltage vs. Supply Voltage 1.4 1.4 1.3 1.3 1.2 1.2 VEN(L) (V) VEN(H) (V) EN Input High Voltage vs. Supply Voltage 1.1 1 -40C 25C 85C 0.9 1.1 1 -40C 25C 85C 0.9 0.8 0.8 3 4 5 6 7 8 9 10 11 12 13 14 3 4 5 6 Supply Voltage (V) VOUT (2V/div) 7 8 9 10 11 12 13 14 Supply Voltage (V) Turn On Delay Time Turn Off Delay Time (VIN = 5.0V, RO = 10) (VIN = 5.0V, RO = 10) 0V VOUT (2V/div) 5.0V EN (2V/div) 0V EN (2V/div) 0V Time (2ms/div) Time (2ms/div) Over-Voltage Protection Response Over-Voltage Response Time (VIN = 5V, OVP Transient from 0.8V to 1.2V) VIN (5V/div) OVP (1V/div) OVP (1V/div) VOUT (2V/div) VOUT (100mV/div) FLT (5V/div) FLT (5V/div) Time (500ns/div) Time (5s/div) 8 0.7s www.analogictech.com 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Functional Block Diagram Fixed Option (metal programable) IN OUT OVP Sense and Control OVP EN GND Functional Description The AAT4687 provides up to 28V over-voltage protection when powering low-voltage systems such as cell phones, MP3, and PDAs or when charging Lithium-Ion batteries from a poorly regulated supply. The AAT4687 is inserted between the power supply or charger source and the load to be protected. The AAT4687 IC includes a low resistance P-channel MOSFET, under-voltage lockout protection, over-voltage monitor, fast shut-down circuitry, and a fault output flag. In normal operation the P-channel MOSFET acts as a slew-rate controlled load switch, connecting and disconnecting the power supply from IN to OUT. A low resistance MOSFET is used to minimize the voltage drop between the voltage source and the load and to reduce power dissipation. When the voltage on the input 4687.2009.09.1.0 FLT exceeds the over-voltage protection trip voltage (internally set in the fixed voltage version or externally by a voltage divider to the OVP pin for the adjustable version), the device immediately turns off the internal P-channel FET, disconnecting the load from the input and preventing damage to downstream components. Simultaneously, the fault flag is raised, alerting the system to a problem. If an over-voltage condition is applied at the time of the device enable, then the switch will remain OFF. Under-Voltage Lockout (UVLO) The AAT4687 has a fixed 3.0V under-voltage lockout level (UVLO). When the input voltage is less than the UVLO level, the MOSFET is turned off. 100mV of hysteresis is included to ensure circuit stability. www.analogictech.com 9 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Application Information Over-Voltage Protection (OVP) The AAT4687 adjustable version has a 1.1V 1.5% overvoltage trip threshold on the OVP pin. With a resistor divider on the OVP pin from IN to GND, the over-voltage trip point can be adjusted anywhere within the input voltage range (see Table 1). Once the over-voltage trip level is triggered, the PMOS switch controller will turn off the PMOS in less than 0.7s. The AAT4687 fixed version is also available, in which the resistor divider is internally integrated with the input voltage trip point at 6.5V. The fixed version of the AAT4687 does not have a connection to the internal OVP circuitry and Pin 1 is designed to be left unconnected. Over-Temperature Protection (OTP) If the ambient temperature of the device exceeds TSHDN, the OVP switch is turned off, and the pin is driven low. The OVP switch will recover automatically when the junction temperature falls below TSHDN - 20C. Fault Indicator (FLT) The output is an active-low open-drain fault reporting output. A pull-up resistor should be connected from FLT to the logic I/O voltage of the host system. FLT will be asserted immediately if an over-voltage or over-temperature fault occurs. Enable Control (EN) EN is an active-low enable input. EN is driven low, connected to ground, or left floating for normal device operation. Taking the EN high turns off the MOSFET. In case of an over-voltage or UVLO condition, toggling the EN will not override the fault condition and the switch will remain off. Device Operation On initial power-up, if VIN < VUVLO or if VOVP > VOVP_TH (1.1V), the PMOS is held off. If VUVLO < VIN, VOVP < VOVP_TH, and EN is low, the device enters startup after a 10ms internal delay. Over-Voltage Protection The AAT4687 over-voltage protection circuit provides fast protection against transient voltage spikes and short duration spikes of high voltage from the power supply lines. The AAT4687 can quickly disconnect the input supply from the load and avoid damage to sensitive components. In portable product applications, if the user removes the battery pack during charging, this action can create large transients and a high voltage spike can occur which can damage other electronic components in the product such as the battery charger. A "hot plug" of the AC/DC wall adapter into the AC outlet can create and release a voltage spike from the transformer. As a result, some sensitive components within the product can be damaged. With the AAT4687 placed between the power lines and the sensitive devices, they are insulated from the voltage spike and the input supply is disconnected in 0.7s. Figure 2 shows the over-voltage protection response time of the test circuit (Figure 1) with R1 = 487k, R2 = 110k, COUT = 1F and ROUT = 10. The input voltage is rapidly increased from 5V to 12V by a voltage surge or voltage spike. The voltage at the OVP pin is also increased until it reaches the over-voltage trip point. At this point, the FLT pin is pulled low and the output voltage starts to fall. Figure 3 shows a zoom-in scope capture of the OVP response time; the output is disconnected from the input in as little as 0.7s. Adjustable Version Over-Voltage Protection Resistors The over-voltage protection threshold is programmed with two resistors, R1 and R2. To limit current flow through the external resistor string while maintaining good noise immunity, use smaller resistor values, such as 10k for R2. Using a larger value will further reduce system current, but will also increase the impedance of the OVP node, making it more sensitive to external noise and interference. A suggested value for R2 is 110k. In the case of R2 = 110k and VOVP_TH = 1.1V, R1 can be approximated by the following formula: R1 = VOVPT VOVPT - 1 * R2 = - 1 * 110 VOVP_TH 1.1 (Voltage in V, Resistance in k) 10 www.analogictech.com 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch SCOPE +12V LOAD AAT4687 10 Vin 1 2 3 4 8 7 6 5 gnd Vout GND +5V OVP Fault Figure 1: Over-Voltage Protection Response Time Test Circuit. VIN (5V/div) OVP (1V/div) OVP (1V/div) VOUT (2V/div) VOUT 100mV/div) FLT (5V/div) FLT (5V/div) Time (5s/div) Time (500ns/div) Figure 2: Typical Over-Voltage Response Time. 4687.2009.09.1.0 0.7s Figure 3: Typical Over-Voltage Response Time (Zoom View). www.analogictech.com 11 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Table 1 summarizes resistor values for various overvoltage settings. Use 1% tolerance metal film resistors for programming the desired OVP setting. R2 (k) R1 (k) VOVPT Setting (V) 110 110 110 110 110 110 110 110 110 110 110 387 487 536 787 1000 1300 1540 1780 2050 2320 2550 5.0 6.0 6.5 9.0 11.0 14.0 16.5 19.0 21.5 24.0 26.5 Table 1: Recommended OVP Setting for AAT4687 Adjustable Version. Input Capacitor A 1F or larger capacitor is typically recommended for CIN. CIN should be located as close to the device VIN pin as practically possible. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor equivalent series resistance (ESR) requirement for CIN. However, for higher current operation, ceramic capacitors are recommended for CIN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources such as batteries in portable devices. Capacitors are typically manufactured in different voltage ratings. If the maximum possible surge voltage is known, select capacitors with a voltage rating at least 5V higher than the maximum possible surge voltage. Otherwise, 50V rated capacitors are generally good for most OVP applications to prevent any surge voltage. Output Capacitor A 0.1F~47F output capacitor is required at the output. Likewise, with the output capacitor, there is no specific capacitor ESR requirement. COUT may be increased to accommodate any load transient condition. Thermal Considerations and Maximum Output Current The AAT4687 is designed to deliver a continuous output load current. The limiting characteristic for maximum safe operating output load current is package power 12 dissipation. In order to obtain high operating currents, careful device layout and circuit operating conditions must be taken into account. The following discussions will assume the load switch is mounted on a printed circuit board utilizing the minimum recommended footprint as stated in the "Printed Circuit Board Layout Recommendations" section of this datasheet. At any given ambient temperature (TA), the maximum package power dissipation can be determined by the following equation: PD(MAX) = TJ(MAX) -TA JA Constants for the AAT4687 are maximum junction temperature (TJ(MAX) = 125C) and package thermal resistance (JA = 160C/W). Worst-case conditions are calculated at the maximum operating temperature, TA = 85C. Typical conditions are calculated under normal ambient conditions where TA = 25C. At TA = 85C, PD(MAX) = 250mW. At TA = 25C, PD(MAX) = 625mW. The maximum continuous output current for the AAT4687 is a function of the package power dissipation and the RDS of the MOSFET at TJ(MAX). The maximum RDS of the MOSFET at TJ(MAX) is calculated by increasing the maximum room temperature. For maximum current, refer to the following equation: IOUT(MAX) = PD(MAX) RDS The maximum allowable output current for the AAT4687 is 1.8A. If the output current exceeds 1.8A, the device will be damaged. Printed Circuit Board Layout Recommendations For proper thermal management and to take advantage of the low RDS(ON) of the AAT4687, certain circuit board layout rules should be followed: VIN and VOUT should be routed using wider than normal traces, and GND should be connected to a ground plane. To maximize package thermal dissipation and power handling capacity of the AAT4687 SC70JW-10 package, the ground plane area connected to the ground pins should be as large as possible. For best performance, CIN and COUT should be placed close to the package pins, as shown in Figures 5 and 6. www.analogictech.com 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Evaluation Board Schematic +5V DS1 Red LED VIN U1 AAT4687 5 C1 1F R1 499k 8 9 10 1 IN GND GND GND OVP FLT OUT OUT EN GND 3 7 6 VOUT R3 1.5k 4 2 C2 1F R2 110k C3 JP1 Enable Figure 4: AAT4687 Evaluation Board Schematic. Component Part Number Description Manufacturer U1 R1 R2 R3 C1 C2 C3 D1 AAT4687 RC0603FR-07499KL RC0603FR-07110KL RC0603FR-071K5L GRM31MR71H105K GRM21BR71C105K Not populated 0805KRCT Over-Voltage Protection Switch RES 499K 1/10W 1% 0603 SMD RES 110K 1/10W 1% 0603 SMD RES 1.5K 1/10W 1% 0603 SMD Cap Ceramic 1F 1206 X7R 50V 10% Cap Ceramic 1F 0805 X7R 16V 10% Analogic Tech Red LED 0805 HB Yageo Murata Table 2: AAT4687 Evaluation Board Bill of Materials. Evaluation Board Layout Figure 5: AAT4687 Evaluation Board Component Side Layout. 4687.2009.09.1.0 Figure 6: AAT4687 Evaluation Board Solder Side Layout. www.analogictech.com 13 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Ordering Information Package OVP Trip Voltage Marking4 Part Number (Tape and Reel)5 SC70JW-10 SC70JW-10 Adjustable 6.5V 7QXYY AAT4687IJQ-T1 AAT4687IJQ-6.5-T1 All AnalogicTech products are offered in Pb-free packaging. The term "Pb-free" means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/aboutus/quality.php. Package Information SC70JW-10 2.20 0.20 1.75 0.10 0.40 BSC 0.225 0.075 Top View 0.100 7 3 0.45 0.10 4 4 0.05 0.05 0.15 0.05 1.10 MAX 0.85 0.15 2.00 0.20 2.10 0.30 Side View End View All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 14 www.analogictech.com 4687.2009.09.1.0 PRODUCT DATASHEET AAT4687 OVPSwitchTM Over-Voltage Protection Switch Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 (c) Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech's terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. 4687.2009.09.1.0 www.analogictech.com 15